Critical Thinking Introduction. Arguments An argument is a series of statements, one of which is offered as a statement to be supported, and the rest.

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Presentation on theme: "Critical Thinking Introduction. Arguments An argument is a series of statements, one of which is offered as a statement to be supported, and the rest."— Presentation transcript:

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Arguments An argument is a series of statements, one of which is offered as a statement to be supported, and the rest of which are offered as support. A conclusion is a statement to be supported. A premise is a statement that offers support.

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Arguments 1) All dogs are mammals. 2) All mammals are animals. 3) [So] All dogs are animals.

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Arguments Question: What do you do with witches? Answer: Burn them. Question: And What do you burn apart from witches? Answer: Wood. Question: Does wood float in water? Answer: Yes. Question: What also floats in water? Answer: A duck.

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Validity A valid argument is one in which it is impossible for the premises to be true while the conclusion is false—i.e., if the premises are true, then the conclusion must be true as well. An invalid argument is one in which it is possible for the premises to be true while the conclusion is false.

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Validity 1) Rex is a dog. 2) All dogs are mammals. 3) [So] Rex is a mammal.

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Validity 1) Rex is a dog. 2) Most dogs are pets. 3) [So] Rex is a pet.

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Soundness A sound argument is a valid argument with all true premises. An unsound argument is an argument that is either invalid or has a false premise.

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Arguments 1) All dogs are mammals. 2) All mammals are animals. 3) [So] All dogs are animals.

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Fallacies A fallacy is a bad argument with the power to persuade. False dilemma Straw Man Equivocation

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False Dilemma A false dilemma is an argument that presupposes there are only two options on some issue, when in fact there are more.

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False Dilemma Y ou are either building fences or you’re learning Spanish. -Stephen Colbert September 26 th, 2007 E ither you are with us, or you are with the terrorists. -George W. Bush September 20 th, 2001

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False Dilemma 1) You don’t support the War. 2) If you don’t support the War, you support terrorism. 3) You support terrorism.

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Straw Man A straw man is an argument that attacks a misrepresentation of some view and then concludes that the view is false. 1) The variety and complexity of life on earth could not have arisen by random chance. 2) If that’s the case, then evolution is wrong. 3) Evolution is wrong.

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Straw Man Y ou have perhaps noted that global warming has struck Washington, hard. Since Gore behind talking about this nonsense, the weather has gone cold all over North America: We’ve had record storms in the Midwest; we have a record low temperature right now at Washington, D.C., for this time of year. So, everything seems to be say, God seems to be saying “Gore is wrong!” -Lyndon Larouche

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Equivocation The fallacy of equivocation occurs when someone uses the same word in two different ways. 1) Man is the only rational creature. 2) Hilary Clinton isn’t a man. 3) [So] Hilary Clinton isn’t a rational creature.

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Equivocation Dana Jacobson (on ESPN radio): I love college football because every game matters. Desk Editor: Just try telling that to Boise St.! They won every game and still got shut out of the championship game!

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Equivocation T here are 365 days in the year, but the average person only works 8 hours a day. That’s one-third of a 24-hour day. So the average person only works the equivalent of one-third of 365 days—that is, about 122 days. However, the average person doesn’t work on the weekends. This means 2 days off a week. There are 52 weeks in a year, so there are 104 days off per year. Subtracting this from 122 days leaves only 18 days. But the average person gets at least this many days off each year between holidays and vacation time. So the average person doesn’t work at all.

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Critical Thinking C ritical reflection plays in important part in our growing up, insofar as we come to think about ideas, beliefs and attitudes that we have picked up along the way from parents, teachers and friends. When we are young we tend to absorb belief and attitudes unthinkingly, and to that extent we are little more than passive products of our environment. But is also possible for us to think critically about them. We many end up accepting or rejecting them, but whatever position we end up with, it will be one that we have decided for ourselves, for our own reasons. -Falzon, “The Holy Grail”

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Critical Thinking [ C ritical thinking] provides us with a way of defending ourselves against manipulation and control by others… we are no longer simply at the mercy of whatever others tell us to believe. We no longer take things at face value. We can critically weigh up the positions being presented to us, to see if there are in fact good reasons for believing them. -Falzon, “The Holy Grail”